Comprehensive investigation on the electrical characteristic and irradiation response of SiC MOS capacitors with EU2O3 dielectrics

This study provides an in-depth analysis of Al/Eu₂O₃/SiO₂/4H-SiC MOS capacitors, employing a dual gate dielectric stack of Eu₂O₃ and SiO₂ on 4H-SiC to enhance device performance. The transition in film structure due to heat treatment was confirmed through X-ray diffraction and atomic force microscopy, revealing optimal crystallization and reduced stress at 800 °C. Electrical measurements show that moderate temperature annealing enhances capacitance stability and decreases interface state density, leading to adjustments in flat band voltage. The device characteristics were notably affected by series resistance. The presence of thermally grown SiO₂ was found to enhance the electrical properties of the devices even at higher annealing temperatures. However, a significant degradation in barrier height was observed, likely attributed to carbon migration and the formation of parasitic silicates at temperatures above 600 °C. On the other hand, the effect of X-rays on the structural and electrical properties of Eu₂O₃ dielectric thin films was studied. The films were exposed to different periods of radiation, and their structural modifications were evaluated using X-ray diffraction (XRD). Meanwhile, the electrical properties were measured by capacitance-voltage (C-V) and conductance-voltage (G/ω-V) techniques. The results indicated that longer exposure to radiation resulted in a decrease in lattice strain and an increase in crystal volume, which can be attributed to the local heating and rearrangement of atoms induced by radiation. Electrical analysis revealed slight shifts in the flat voltage and mid-gap due to defects induced by radiation, affecting the charge-trapping behavior. Despite these defects, the dielectric material showed stable electrical performance under the tested radiation conditions, indicating its potential for use in radiation-resistant electronic devices. These results confirm the potential application of Eu₂O₃ films as a highly efficient dielectric material in such technologies. It can be said that this research demonstrates a promising insulating structure on 4H-SiC that balances crystallinity and defect control, which makes MOS devices a suitable candidate for future applications. KEYWORDS: 4H–SiC, MOS Capacitor, Eu2O3, MOS Irradiation, High-K